With fashionable design and small size, the OSUB 40w kit is a popular kit from Smok. It uses C-shaped magnetic side-cover design, and you can see the fire key connect and Micro-USB charging port clearly after remove the magnetic side-cover. The OSUB 40W features 1350mah capacity internal battery and support 40w output, it can ensure enough vaping time in a party. The 22mm Helmet mini tank comes with U-shaped tube and top airflow system. It is very easy to refill and no leaking problem.